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package service;

import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.LockModeType;
import javax.persistence.NoResultException;
import javax.persistence.Query;

/**
 *
 * @author GROSSEL
 */
public abstract class AbstractFacade<T> {
    private Class<T> entityClass;

    public AbstractFacade(Class<T> entityClass) {
        this.entityClass = entityClass;
    }

    protected EntityManager em;
    protected abstract EntityManager getEntityManager();

  public AbstractFacade(EntityManager em) {
    this.em = em;
  }

    
    public void create(T entity) {
        getEntityManager().persist(entity);
    }

    public void edit(T entity) {
        getEntityManager().merge(entity);
    }

    public void remove(T entity) {
        getEntityManager().remove(getEntityManager().merge(entity));
    }

    public T find(Object id) {
        return getEntityManager().find(entityClass, id);
    }

    public List<T> findAll() {
        javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
        cq.select(cq.from(entityClass));
        return getEntityManager().createQuery(cq).getResultList();
    }

    public List<T> findRange(int[] range) {
        javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
        cq.select(cq.from(entityClass));
        javax.persistence.Query q = getEntityManager().createQuery(cq);
        q.setMaxResults(range[1] - range[0]);
        q.setFirstResult(range[0]);
        return q.getResultList();
    }

    public int count() {
        javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
        javax.persistence.criteria.Root<T> rt = cq.from(entityClass);
        cq.select(getEntityManager().getCriteriaBuilder().count(rt));
        javax.persistence.Query q = getEntityManager().createQuery(cq);
        return ((Long) q.getSingleResult()).intValue();
    }

     public String findQuery(String firstName, String lastName  ) {
         /*Students.findStudents
        return getEntityManager().find(entityClass, firstName , lastName);
        return getEntityManager().find(entityClass, lastName, LockModeType.READ);*/
        
         Query q = em.createNamedQuery("Students.findStudents").setParameter("lastName",
          lastName).setParameter("firstName", firstName);

      return  ("dfd"); 


     }
        
    
}
